Page 129 - Remedial Andrology

10. MALE INFERTILITY

10.1 Definition and classification
Infertility is defined by the inability of a sexually active, non-contraceptive couple to achieve spontaneous
pregnancy within 1 year [1439]. Primary infertility refers to couples that have never had a child and cannot
achieve pregnancy after at least 12 consecutive months having sex without using birth control methods.
Secondary infertility refers to infertile couples who have been able to achieve pregnancy at least once before
(with the same or different sexual partner). Recurrent pregnancy loss is distinct from infertility and is defined as
two or more failed pregnancies [1440, 1441].

10.2 Epidemiology/aetiology/pathophysiology/risk factors
10.2.1 Introduction
About 15% of couples do not achieve pregnancy within 1 year and seek medical treatment for infertility. One
in eight couples encounter problems when attempting to conceive a first child and one in six when attempting
to conceive a subsequent child [1442]. In 50% of involuntarily childless couples, a male-infertility-associated
factor is found, usually together with abnormal semen parameters [1439]. For this reason, all male patients
belonging to infertile couples should undergo medical evaluation by a urologist trained in male reproduction.

Male fertility can be impaired as a result of [1439]:
• congenital or acquired urogenital abnormalities;
• gonadotoxic exposure (e.g., radiotherapy or chemotherapy);
• malignancies;
• urogenital tract infections;
• increased scrotal temperature (e.g., as a consequence of varicocele);
• endocrine disturbances;
• genetic abnormalities;
• immunological factors.

In 30-40% of cases, no male-associated factor is found to explain impairment of sperm parameters and
historically was referred to as idiopathic male infertility. These men present with no previous history of diseases
affecting fertility and have normal findings on physical examination and endocrine, genetic and biochemical
laboratory testing, although semen analysis may reveal pathological findings (see Section 10.3.2). Unexplained
male infertility is defined as infertility of unknown origin with normal sperm parameters and partner evaluation.
Between 20 and 30% of couples will have unexplained infertility. It is now believed that idiopathic male
infertility may be associated with several previously unidentified pathological factors, which include but are not
limited to endocrine disruption as a result of environmental pollution, generation of reactive oxygen species
(ROS)/sperm DNA damage, or genetic and epigenetic abnormalities [1443].

Advanced paternal age has emerged as one of the main risk factors associated with the progressive increase
in the prevalence of male factor infertility [1444-1451]. Likewise, advanced maternal age must be considered
over the management of every infertile couple, and the consequent decisions in the diagnostic and therapeutic
strategy of the male partner [1452, 1453]. Therefore, this should include the age and ovarian reserve of the
female partner, since these parameters might determine decision-making in terms of timing and therapeutic
strategies (e.g., assisted reproductive technology [ART] versus surgical intervention) [1444-1447]. Table 39
summarises the main male-infertility-associated factors.

Table 39: Male infertility causes and associated factors and percentage of distribution in 10,469 patients
[1454]

Diagnosis Unselected patients Azoospermic patients
(n = 12,945) (n = 1,446)
All 100% 11.2%
Infertility of known (possible) cause 42.6% 42.6%
Maldescended testes 8.4 17.2
Varicocele 14.8 10.9
Sperm auto-antibodies 3.9 -
Testicular tumour 1.2 2.8
Others 5.0 1.2
Idiopathic infertility 30.0 13.3

128 SEXUAL AND REPRODUCTIVE HEALTH - MARCH 2021